For two decades, Charlie Sheen's personal life has been a battlefield of bitter ex-wives, broken engagements, porn stars, hookers, drug-fueled orgies, and domestic discord. No wonder his prenup—which we revealed yesterday—is so obsessed with minimizing risk.

For the Charlie Sheens of the world, "I do" is not a leap of faith, but a tightly bound, rigorously negotiated economic transaction. Living expenses are pre-determined; tokens of affection are quantified in dollars; monies are kept separate. So why bother marrying at all? Or maybe the real question is—why not? If it's set up properly, you don't have to risk a thing.

With every marriage, Sheen has gotten better at cutting his losses. If third wife Brooke Mueller were to walk away today, just shy of three years of marriage, she would collect $3.5 million. Though this is a very substantial large sum by any normal measure, it's nothing compared to second wife (also of three years) Denise Richards' rumored $40 million settlement. Among other pro-Denise stipulations, Richards' prenup apparently had a $4 million infidelity clause.

In other words, dicking around on Denise could cost Charlie more than his entire marriage to Brooke. (But less than Michael Douglas loses if he dicks around on Catherine Zeta-Jones: $5 million per indiscretion. And less than Jesse James lost for cheating on Sandra Bullock: Their prenup allegedly specified he'd get nothing if he strayed.)

The stipulations aren't always financial, either. To marry Nicole Kidman, the formerly drug-addicted Keith Urban reportedly agreed to preemptive rehab—Tom Cruise required it if Urban was to interact with the Cruise-Kidman children—and an "escape clause" for Nicole should he relapse. (The prenup also provided that the famous country music star would receive a $640,000 annual allowance from his even more famous wife.) Diane Richie's alimony from Lionel included $20,000 annual plastic surgery stipend. Should Khloe Kardashian and Lamar Odom break up, Khloe specifies that Lamar must provide her entire family courtside Lakers tickets. Apparently the Kardashians want to watch Lamar play even if he's not part of their family.

Of course, there are always those who look for ways to wriggle out. Mick Jagger successfully diminished Jerry Hall's divorce settlement by challenging the legality of their wedding, which occurred in Bali. Steven Spielberg ended up paying $100 million (then half of his fortune) to ex-wife Amy Irving, who successfully had their prenup thrown out because she didn't have a lawyer when she signed it. Which means there might be hope for Brooke Mueller yet.